Simon Spier is a closeted gay teenager attending high school in a suburb of Atlanta, Georgia. Simon has yet to inform his family or friends about his sexual orientation and has begun communicating with an anonymous fellow closeted classmate who goes by the pseudonym "Blue" online, using his own pseudonym of "Jacques". This email exchange is uncovered by fellow classmate Martin, who blackmails Simon by threatening to out him to the entire school unless he helps Martin get a date with one of Simon's best friends. Simon is then forced to balance his friends, his family, and the blackmailer, while simultaneously attempting to discover the identity of the anonymous classmate he has fallen in love with online.